For all his success at the Tour de France over the years, Mark Cavendish (Dimension Data) has never known an opening week quite like this one. The Manxman claimed his third win in just six days – and the 29th Tour stage victory of his career – when he out-lasted Marcel Kittel (Etixx-QuickStep) and Dan McLay (Fortuneo-Vital Concept) in the bunch sprint in Montauban.

In keeping with the tenor of bunch finishes at this year's Tour, it was another rather chaotic finale to stage 6, with no one team capable of taking control of affairs at the head of the peloton, despite the game efforts of Bryan Coquard's Direct Energie squad.

Faced with such tumult, Cavendish opted for a rather straightforward tactic: he sought out his rival Kittel's wheel in the closing kilometres, and then looked to come around him in the finishing straight. Easier said than done, but Cavendish is enjoying a run of form perhaps unseen since his domination of the sprint stages at the 2013 Giro d'Italia: every decision he takes this week appears to be the right one.

Cavendish duly came off Kittel's wheel just inside the final 150 metres and quickly opened a gap. Though both Kittel and the rapidly-closing McLay began to peg him back in as the line drew nearer, Cavendish was not to be denied.

Prior to this week, Cavendish had never beaten Kittel in a head-to-head sprint at the Tour, and the assumption was that the German's recent pre-eminence in that particular prize fight would continue here. Instead, the scorecard reads 3-1 in Cavendish's favour as the mountains appear on the horizon.

"It was just carnage in the final with guys coming left and right. I wanted Kittel's wheel. I was fighting and fighting for Kittel's wheel," Cavendish said afterwards. "Etixx weren't that organised but I knew that they would get it on the final long, fast run-in. I knew it would be the right thing to go early. Because it was slightly downhill, I put on a bigger gear again and I just went. Actually, I maxed out, I should have put a bigger gear on.

"I kept going to the line, I really wanted it. I felt Kittel coming up on my side again but I just did what he's done to me over the last three years and just held him at it."

Kittel was magnanimous in defeat, admitting that Cavendish was "where he needed to be and when." When the peloton entered the final four kilometres, it had been notable that neither Kittel nor any of his Etixx-QuickStep teammates were in the first 25 positions, and the German explained that bunch finishes at this year's Tour have been especially difficult to negotiate.

"To be very honest, in the finals this year, there is no tactic. It's impossible to ride with a team here. I don't know why the organisers do it like this with downhills in the city, we have all those small roads and corners. It goes wide, narrow, wide again and every team is struggling at this stage to be at the front," Kittel said. "The GC teams are also holding their wheels until the finish line. It's pure chaos and that's why you can win here with really smart positioning. The team only has to bring you forward at a certain moment and that's it and then you have to go out of the wheel of someone at a certain point."

That kind of chaos arguably suited McLay more than anyone. The Englishman slalomed to a spectacular victory at the GP Denain earlier in the season, and he picked his way through the traffic here and came within a whisker of springing a surprise victory.

Indeed, McLay's has been a remarkably assured Tour debut. Not many neophytes succeed in participating in a bunch sprint, far less coming so close to claiming a victory, but McLay now has four top-ten finishes under his belt and has justified the faith shown in him by his Fortuneo-Vital Concept team.

Alexander Kristoff, who enjoyed a slightly better lead-out than most from his Katusha team, had to settle for fourth, ahead of Christophe Laporte (Cofidis), while Peter Sagan (Tinkoff) took fifth.

Greg Van Avermaet (BMC) finished safely in the main peloton to keep the yellow jersey and maintain his lead of 5:11 over Julian Alaphilippe (Etixx-QuickStep), with Alejandro Valverde (Movistar) a further two seconds back in third.

Calm before the storm

With the mercury steadily rising in time with the Tour peloton's trajectory south, and with the race set to enter the high mountains on Friday, it was hardly surprising that once an early break formed – step forward Yukiya Arashiro (Lampre-Merida) and Jan Barta (Bora-Argon 18) – the peloton would leave them to it.

The two leaders amassed a maximum advantage just north of five minutes while BMC – with some help from the sprinters' teams – kept tabs on the gap, though there was precious little urgency in the main peloton until deep into the stage.

Arashiro and Barta's gap slipped to less a minute with 40 kilometres to race, and once Direct Energie went through the motions of marshalling the chase in earnest, their day was done, and they were duly swept up with 23 kilometres remaining.

Even at that juncture, however, no one man team managed to bend the finale to its will, and the finale seemed almost placid at times, with riders spread across the road on the front right into the final ten kilometres. As Cavendish pointed out afterwards, however, it was all rather less serene beneath the surface. Nothing is ever straightforward at the Tour.

"Oh my God, that was terrifying. That was like the old days, just wheel surfing," Cavendish said. "Honestly, I said this morning: ‘There are two finish lines, there's one with 12k to go when we got onto the small road.' And we were a little too far back, Bernie [Eisel] and I, going into that."

Cavendish succeeded in navigating the eddying currents of the peloton better than most in the finale, where others unexpectedly ran aground. Lotto Soudal led into the final 1500 metres, for instance, but André Greipel could only manage 15th, while for all Sylvain Chavanel and Direct Energie's work, Coquard had to settle for 9th place. In the end, it was Fabio Sabatini (Etixx-QuickStep) who opened a rather disjointed sprint, but it was his former teammate Cavendish who emerged to claim the spoils.

The general classification contenders, meanwhile, enjoyed a relative day of détente ahead of the upcoming troika of Pyrenean stages, with Chris Froome (Sky), Nairo Quintana (Movistar) and Alberto Contador (Tinkoff) all finishing safely in the main peloton.

Unlike a year ago, Froome and Quintana enter the high mountains locked on the same time, each 5:17 down on Van Avermaet. The Col d'Aspin awaits.